1. Field of the Invention
This invention relates generally to a hybrid electronic and optical circuit switch architecture and, more particularly, to an opto-electronic circuit switch that is able to route analog and digital signals of any bandwidth using a full-broadcast and non-blocking scheme, and is relatively simple to expand.
2. Discussion of the Related Art
Switches perform the routing and distribution of signals in communication systems and have played a pivotal role since the invention of the telephone. Traditionally, these switches were electrical in nature; distributing the information contained in an electrical signal. Over years, data rates, sizes and complexities for communication networks have increased due to greater technological advances in high-speed data communications. The requirements of switches have gone beyond the capabilities of electrical switches, and therefore alternative switching strategies are needed. Today, these switches allows video to join data and voice signals to create multimedia communication systems.
In circuit switch networks, there is always a need for circuit switches with higher number of input/output ports that handle faster data rates per port. Currently, analog circuit switches can route and distribute analog signals of a fixed bandwidth for which it was built, and digital switches typically support only up to 32 1.2 Gbps data streams. In addition, there is a need for a circuit switch that provides 100% non-blocking and also supports full broadcasting. For instance, the Clos switch architecture has full broadcasting capabilities, but offers some probability of blocking certain switching routes.
Moreover, today's switches are based on electronic fabrics made by commercial manufactures; however, some of these companies do not plan or are not able to make faster switch fabrics. Upgrading the analog or digital bandwidth of existing circuit switches is not possible once they have been manufactured. Expanding their size is relatively difficult, expensive and time consuming.
Within the next ten years, circuit switches will need to increase capability in order to support higher bandwidths and larger networks. Opto-electronic switching architectures are an alternative that may meet these criteria while providing more flexibility in size and bandwidth expansion at a lower cost than other architectures.
Therefore, it is desirable to provide a high-bandwidth circuit switching architecture with full broadcasting and non-blocking capabilities. These circuit switches should be expandable in size and upgradable in bandwidth, while maintaining backwards compatibility with existing systems. The opto-electronic circuit switch of the present invention will utilize wavelength division multiplexing, as well as (optionally) frequency division multiplexing and quadrature amplitude modulation to achieve these requirements. To implement this architecture, it is desirable to utilize commercial off-the-shelf components to facilitate expansion, and yet reduce the need for other various expensive optical and electrical components.